1. Field of the Invention
The present invention relates to an apparatus for attaching sand papers semi-automatically onto dummy wafers.
2. Description of Related Art
A probe card is one of the components that form an apparatus for the probe measurement employed in the course of manufacturing semiconductor devices such as transistors and integrated circuits. As shown in FIG. 6, the probing card 20 has a plurality of probes or tips 22 arranged so as to correspond to, and come into electrical contact with, a plurality of electrode pads of semiconductor devices fabricated on a semiconductor wafer, as the electrical characteristics of the semiconductor devices are tested. Because the contact between the electrode pads and the probes is a point contact having a small contact area, the ends of the probes 22 are rounded. Also, the ends of the probes 22 need to be polished in order to prevent them from oxidizing upon contact with air. The polishing is accomplished via a dummy wafer W on which a sand paper 10 is attached.
However, up until now, an operation to prepare the dummy wafer W for polishing, i.e., attaching the sand paper 10 to the dummy wafer W, has been manually carried out. Attaching the sand paper 10 manually to the dummy wafer W may present the following problems. First, after being attached to a dummy wafer, a surface of the sand paper is usually rubbed with a matter such as pieces of paper to enhance the degree of adhesion. As a result of this rubbing, contaminants or foreign substances can be accumulated on the surface of the sand paper deteriorating its function. Secondly, during the attaching, air bubbles can form between the sand paper and the dummy wafer. These air bubbles may impose an impact on the tips of the probes to induce a defect therein during polishing. Thirdly, the sand paper should optimally be attached onto the center of the dummy wafer correctly, as shown in FIG. 6. Attaching the sand paper correctly, however, is not guaranteed when done manually and varies according to the skill or experience of workers. If it is not correctly attached onto the center of the dummy wafer, the resulting dummy wafers will be of inferior quality. Fourthly, it takes significant time to attach the sand paper onto the dummy wafer. For example, it takes a skilled worker one minute to attach one sheet of sand paper. Lastly, since the attaching method can be different according to workers, dummy wafers of inferior quality can thereby be made.
In order to solve the aforementioned problems, it is a feature of an embodiment of the present invention to provide a new apparatus that can easily attach an object onto a dummy wafer.
This and other features are provided, according to the present invention, by an apparatus for attaching an object semi-automatically onto a dummy wafer comprising a stage having a loading surface on which the dummy wafer rests, a pressing means for attaching the object gradually on the dummy wafer placed on the loading surface, and a support means for placing the object in a position spaced apart from the loading surface.
In a preferred embodiment of the present invention, the supporting means includes at least two supporting rods disposed to cross the loading surface at an angle to said loading surface for placing the object thereon, and side plates disposed on opposite sides of the stage for fixing both ends of the support rods.
The supporting means further includes a plurality of mini-rollers disposed on the support rods to allow the object to be easily slid without adhering to the support rods, and a pair of holders disposed apart from each other on the support rods for guiding both sides of the object so that the object may be slid down correctly. The holders are disposed such that the distance between them is adjustable in order to accommodate objects of differing sizes.
The two support rods of the supporting means may be disposed to be inclined, allowing the object to be placed on a slope thereon.
Also, the stage may have openings or grooves formed at an edge of the loading surface to load or unload the dummy wafer easily. The loading surface may also be disposed lower than an upper surface of the stage.
In an embodiment of the present invention, guide rails disposed at both sides of the stage allow the pressing means and the supporting means to be movable so that they may be slid in a direction that will allow the object to be attached onto the dummy wafer.
In the apparatus of an embodiment of the present invention, the pressing means includes a roller for attaching the object onto the dummy wafer, brackets for fixing both ends of the roller rotatably, and a handle connected with the brackets for moving the roller in the direction that will allow the object to be attached onto the dummy wafer. The roller is formed of material having a given elasticity to prevent the dummy wafer from being damaged and to increase the adhesion degree during the attaching of the object.